The report called for clear and simple recycling labelling on all plastic packaging.
Photograph: David Forster/Alamy Stock Photo

Almost a third of plastic packaging used by UK supermarkets is either non-recyclable through standard collection schemes or difficult to recycle, according to a new analysis by a consumer group.

Which? is urging the government to introduce compulsory “clear and simple” recycling labelling on all plastic packaging as its new research reveals “huge inconsistencies” involving myriad different schemes and with some items not labelled at all.

Its analysis of the packaging used for 27 everyday own-brand items at 10 major chains found that Lidl had the lowest proportion of widely recyclable packaging – at 71%. Iceland (73%), Ocado (74%) and Sainsbury’s (75%) were also close to the bottom of the pile. Overall, the analysis found that up to 29% of plastic packaging was not widely recyclable.

The best performer was Morrisons with easily recyclable packaging for 81% of its tested products. For example, Morrisons’ chocolate cake was in a widely recyclable plastic box, while Lidl’s cake came in mixed packaging comprising a non-recyclable film within a widely recyclable box with a non-recyclable window.

The plastic on M&S and Waitrose apples was labelled as non-recyclable, yet the type of plastic they are wrapped in actually is recyclable at supermarket collection points. Other products had labels that were only visible once the food was unwrapped.

“Which? believes a lot more can be done to increase the amount of recyclable packaging and the way it is labelled so that consumers know what can be recycled and how to recycle it” said Nikki Stopford, director of research and publishing at Which? “The plastic pollution crisis makes it more crucial than ever that the government, manufacturers and supermarkets do the best they can to banish plastic that cannot be recycled and promote the use of less damaging packaging.”

The analysis highlighted black plastic trays and “orange nets” as items that remain a huge challenge. The latter are not only non-recyclable, but they can also cause huge problems if they wrongly end up in a recycling sorting plant and risk getting caught in the machinery.

It also found that a significant proportion of packaging – as much as 10% of Waitrose’s goods – could only be recycled at supermarket collection points rather than at the kerbside.

In April, in response to a growing public backlash against the huge volumes of plastic rubbish, Aldi, Asda, Lidl, M&S, Morrisons, Ocado, Sainsbury’s, Tesco and Waitrose all signed up to support the UK Plastics Pact – an industry wide initiative which says it aims to transform packaging and reduce avoidable plastic waste. That includes an aspiration that by 2025 all plastic packaging can be reused, recycled or composted.

A Lidl spokesperson said the company had recently launched ambitious plastic reduction targets. “We are in the process of conducting a comprehensive review of our entire packaging footprint, and estimate that the vast majority of our packaging is widely recyclable under the industry standard scheme.”